This invention relates to a mount or mounting structure for attaching equipment such as a snowplow, bucket loader, fork lift, or the like to a wheeled vehicle, and in particular to such a mount which can support the equipment as unsprung weight on a vehicle having independent front suspension. It is well known to attach equipment such as a snowplow, a dozer bucket, a fork lift, a power broom, some types of mowers, or the like to the front of a wheeled vehicle such as a garden tractor, a small truck, an all-terrain vehicle (ATV), or other vehicle. It is also common to attach other equipment to the rear of such a vehicle, such as a box scraper, a rear angle grader blade, a tines cultivator, a trailing type of mower, a cargo carrier, such as a game carrier, a trailer, or the like. Mounting such equipment on a tractor is a relatively straight forward procedure because tractors do not typically have any suspension system; i.e. the axles of a tractor are rigidly affixed to the chassis. The equipment can, therefore, be mounted in any convenient location on the vehicle with little concern as to the effect of the weight of the equipment on the handling of the vehicle.
When mounting equipment on a truck, ATV, or other vehicle having a suspension, the weight of the equipment becomes a concern. Typically, the equipment is bolted to the frame of the vehicle and the weight of the equipment and any load supported thereon becomes sprung weight, meaning that the weight must be supported by the springs in the vehicle's suspension. Too much sprung weight on the front of a vehicle can cause the front suspension to sag, bottom out, or even collapse and can additionally cause steering problems.
This problem as been previously addressed in vehicles having solid beam-type front axles by supporting the weight of the equipment on the front axle. For example, U.S. Pat. No. 2,091,343 issued to G. C. Soule et al. in 1937 discloses a snowplow mount for a truck with a beam axle. The weight of the snowplow is carried by brackets which hook over and attach to the front axle. The plow is stabilized by a framework which extends rearwardly under the truck and bolts to the truck frame forward of the rear wheels. The result is that the weight of the snowplow is not carried by the truck's suspension, but instead becomes unsprung weight supported only by the axle and front wheels. The only force transmitted to the frame is an upward force near the rear of the vehicle which, due to the length of the framework, is only a fraction of the weight of the plow. Similar inventions are disclosed by Canadian Patent Nos. 326,141 and 535,370.
With some types of equipment that is connected to the front or rear of such vehicles, it is desirable to have a means of raising or lowering the equipment. For example, a front or rear mounted scraper blade needs to be lowered when scraping is needed and raised for traveling to the worksite or in maneuvering about the worksite. Small tractors and all terrain vehicles typically are not equipped with hydraulic cylinders for such raising and lowering of equipment. However, some vehicles of these types are equipped with winches.
While equipment mounts as described above work acceptably well in older vehicles or large trucks having solid front axles, they are not applicable to newer light trucks, sport utility vehicles, or ATVs having independent front suspension since these vehicles have no axle to which to attach the equipment mount. What is needed is an improved equipment mount capable of mounting equipment on a wheeled vehicle wherein the mount is designed to support the equipment as unsprung weight. U.S. Pat. Nos. 6,931,770 and 7,093,381, issued to one of the inventors of the present invention and incorporated herein by reference, disclose a mounting structure for attaching equipment to the front of an ATV and which is connected at a rear end to the vehicle chassis and to the front axles of the vehicle. However, the '770 and '381 patents do not provide a means for attaching equipment to the rear of such a vehicle or for raising and lowering such equipment either at the front or at the rear.